This invention relates to a material used to extinguish forest fires as well as high temperature fires in building structures,
Background and description. In burning wood fires, the reaction between the water and carbon in wood produces water gas--a mixture of carbon monoxide and hydrogen--both substances being combustible. When a building catches fire and the temperature rises rapidly it can be controlled by using large volumes of water to bring the temperature below its kindling temperature, and at the same time quench the water gas reaction.
In some instances like forest fires where water is insufficient, high ambient temperatures during summer fanned by strong winds, it is almost impossible to control the spread of the fire. Sometimes a dry chemical-suppressant is used.
In the aerial application of liquid fire suppressant materials it has been found that these substances tend to atomize when dropped from substantial elevations. On the other hand, materials of high viscosity such as clay slimes tend to resist atomization upon descent to target areas.
The colloidal behavior of certain clays such as those produced in the beneficiation of phosphate ore in Florida commonly called "slimes" appears to effectively control or extinguish these fires.
The mining of phosphate ore in Central Florida is done by an open-pit method whereby the overburden is stripped to expose the phosphate ore called "matrix". The thickness of the matrix varies from one to fifty feet and consist essentially of 1/3 phosphate ore, 1/3 sand and 1/3 clay. The matrix is mined by a walking electrical dragline and the ore is hydraulically transported from the mining site to the beneficiation plant. The matrix is initially sized and washed to produce a 3/4 inch to +16 mesh (Tyler mesh) of pebble product. The -16 mesh material is then subjected to a desliming operation to remove most of the -150 mesh waste material.
The suspension of -150 mesh waste slime is then transferred to a settling pond built in a mined out area. The solids slowly settle to produce an upper layer of clear water which is recycled back to the plant for further use. The composition of the slimes vary according to the mineralogical composition of the matrix from which it was mined. In Central Florida these consist essentially of montmorillonite and attapulgite together with some other minerals such as flourspar, quartz, and flourapatite, etc. The montmorillonite and attapulgite which are known for their water holding capacity and colloidal behavior contribute to the slow settling property of the slimes. Slimes that are transported to the impounding area contain approximately 1.5 to 3.5% solids. Over time the concentration of the slimes will attain steady state of about 25 per cent solids after several years of storage. It has been estimated that there are more than 1.5 billion tons of phosphatic clay slime solids stored in these dams. The storage of these slimes poses an environmental problem should the dams break and flood the surrounding areas with clay slimes. Furthermore, considerable amount of water that is stored in these dams are practically unusable.